共查询到20条相似文献，搜索用时 46 毫秒
1.
High performance fibers have distinguished properties such as high tensile strength, good thermal and chemical resistance, dimensional stability, lightweight, and high electrical conductivity. Due to these superior properties, high performance fibers made it to the scene of broad range of applications such as aerospace, automotive, windmill, fiber reinforced composites, high strength tethers, tendons for scientific balloon, tension structures, protective clothing, and marine. Examples of such fibers are Zylon®, Kevlar®, and Vectran®. However, the fibers lose their strength significantly upon exposure to Ultraviolet (UV) and visible light. In this research, UV protective films from extruded low density polyethylene (LDPE) loaded with different content of UV stabilizers (TiO2 nanoparticles and White PE CC®) were investigated. To assess the degree of UV blockage of each extruded protective film, their transmittance to UV and visible (UV-VIS) light was measured. Additionally, Zylon® braids were sheathed with the protective films and the strength of the braids and yarns raveled from braids was measured before and after UV exposure for different number of days. LDPE loaded with White PE CC® and 10 % TiO2 showed the least transmittance to UV-VIS and their yarns and braids exhibited highest strength retention after exposure to artificial UV. Strength retention of braids was higher than that of individual yarns due to weak link effect and braid structure assistant. 相似文献
2.
Silk sutures are already used in surgery. Silk is a natural protein fiber and easily prone to microbial infection hence we have developed novel antimicrobial silk braided sutures. Braided silk sutures were fabricated using a circular braiding machine with a 16 carrier arrangement normally used to produce braided structures. The same structure was used to manufacture braids with three different take-up speed levels obtained by changing the cogwheel ratio on the braiding machine. The influence of braid angle, test parameters such as gauge length and extension rate on tenacity and knot strength of braided silk sutures were studied. Silk sutures fabricated at higher braid angle, tested at shorter gauge length and greater test speed showed lower values of tenacity and knot strength. Chitosan was applied on braided silk sutures to impart antimicrobial characteristics. The Scanning electron microscopy study reveals the absence and presence of chitosan on the surface of untreated and treated sutures respectively. The antimicrobial properties of chitosan and tetracycline hydrochloride drug were tested using Agar diffusion method SN 195920 both when applied independently and collectively on silk sutures against Escherichia coli and Staphylococcus aureus. The combined antimicrobial effect of chitosan and tetracycline hydrochloride drug is very good and can be used to develop antimicrobial silk sutures for providing protection against microbial infections. 相似文献
3.
Polyacrylonitrile (PAN) nanofiber filaments were manufactured continuously for several hours by a homemade multi-needle electrospinning device. The yarns were continuously obtained by plying and twisting nanofiber filaments using a self-made twisting device. The structures and mechanical properties of yarns were investigated. The influences of twist setting temperatures and periods of time on morphology and mechanical properties were discussed. The results showed that the alignment degree of nanofibers along the filament axis could reach 70.9 %. The twist angle increased with increasing twists and the number of filaments. With increasing twists, the breaking stress and strain increased initially and then decreased; the maximum breaking stress and strain were 34.7 MPa and 26.1 %, respectively; the initial modulus decreased with increasing twists and plies, the maximum modulus was 391.3 MPa. Both the breaking stress and strain increased with the increase of twist setting temperatures and times. The optimal setting temperature and time were 90 °C and 30 min, respectively, the maximum breaking stress and strain were 32.8 MPa and 20.8 %, meanwhile, the crystallinity improved from 34.5 % to 39.9 %. This study demonstrates the possibility of continuously and stably manufacturing PAN nanofiber yarns. 相似文献
4.
Studies on reduction of yarn hairiness by nozzles in ring spinning and winding by airflow simulation
Reduction of yarn hairiness by nozzles in ring spinning and winding is a new approach. Simulation of the airflow pattern inside
the nozzles provides useful information about actual mechanism of hairiness reduction. The swirling air current inside the
nozzles is capable of wrapping the protruding hairs around the yarn body, thereby reducing yarn hairiness. Since production
rate of winding is very high and the process itself increases yarn hairiness any method to reduce the hairiness of yarns at
this stage is a novel approach. A CFD (computational fluid dynamics) model has been developed to simulate the airflow pattern
inside the nozzles using Fluent 6.1 software. In this study, both S- and Z-type nozzles having an axial angle of 50° and diameter
of 2.2 mm were used for simulation studies. To create a swirling effect, four air holes of 0.4 mm diameter are made tangential
to the inner walls of the nozzles. S- and Z-twisted yarns of 30 tex were spun with and without nozzles and were tested for
hairiness, tensile and evenness properties. The total number of hairs equal to or exceeding 3 mm (i.e. the S3 values) for
yarn spun with nozzle is nearly 49–51 % less than that of ring yarns in case of nozzle-ring spinning, and 15 % less in case
of nozzle-winding, while both the yarn types show little difference in evenness and tensile properties. Upward airflow gives
best results in terms of hairiness reduction for nozzle-ring and nozzle wound yarns compared to ring yarns. Yarn passing through
the centre of the nozzle shows maximum reduction in S3 values. 相似文献
5.
This study reports on the analysis of tenacity and breaking elongation of ring-, rotor- and air-jet-polyester/viscose spun
yarns measured using static- and dynamic tensile testers. The weavability, a measure of performance of these yarns in post
spinning operations is quantified. The yarn diameters and helix angles of fibres in these yarns are measured in order to analyze
the effect of types of spun yarn and blend proportion on yarn elongations. The dynamic tenacity is highly correlated with
the weavability than the average static tenacity measured at 500 mm gauge length. The minimum static tenacity obtained from
100 tests has high correlation with the dynamic tenacity. The present study indicates that it is appropriate to evaluate the
performance of spun yarns in winding, warping and weaving based on the dynamic yarn tenacity measured while running a 200
m length of yarn in a constant tension transport tester or the minimum static yarn tenacity obtained using any conventional
constant rate extension (CRE) tensile testers corresponding to a total test length of 50 m. 相似文献
6.
Blending of nylon filament with viscose can overcome the drawbacks of these yarns. Thermoplastic and thermoset filament yarns
can be blended in air-jet texturising method. The characteristics of nylon/viscose blended filament yarns are required to
be understood in order to convert them in to useful products. Therefore, nylon/viscose blended yarns in different proportions
were produced using nylon 6 and viscose filament yarns in air jet texturising machine. The textured yarns were also produced
in dry and pre-wet conditions to understand the effect of water on textured yarn characteristics. It was found that the loops
frequency, bulkiness of nylon/viscose blended textured yarns increase with increase in viscose proportion. The Loops stability,
tenacity and breaking elongation decrease with increase in viscose proportion. Pre-wet textured yarn show higher loops, bulkiness,
and good loop stability than their corresponding dry textured yarns. 相似文献
7.
The dynamic testing conditions simulate actual manufacturing conditions more closely than static testing. In most cases, as results from dynamic tests differ significantly from static tests, dynamic tests are more relevant from the point of view of processing of yarn. The yarns are in motion when they are running on different machines during the production process viz. weaving; knitting etc. Compact ring spun yarns have created a fundamental change how the industry views the ring spinning. The new technology compact yarns such as EliTe® yarns need to be compared with the normal doubled yarns in a dynamic way. This study involves dynamic testing of the EliTe® compact yarns and normal ring spun doubled yarns using CTT (Constant Tension Transport) machine, a versatile test instrument to measure the yarn properties such as dynamic breaking strength, elongation, abrasion, lint, yarn faults (thick, thin places, neps), hairiness etc. EliTe® compact yarns showed higher breaking strength, more elongation, with lesser yarn faults and hairiness, less abrasiveness and less lint generating tendencies during the dynamic testing as compared to the normal ring spun doubled yarns. 相似文献
8.
In this study, an analysis on the breaking elongation mechanism of the polyester/viscose blended open-end rotor spun yarns
has been carried out. In addition, a back propagation multi layer perceptron (MLP) network and a mixture process crossed regression
model with two mixture components (polyester and viscose blend ratios) and two process variables (yarn count and rotor speed)
are developed to predict the breaking elongation of polyester/viscose blended open-end rotor spun yarns. Seven different blend
ratios of polyester/viscose slivers are produced and these slivers are manufactured with four different rotor speed and four
different yarn counts in rotor spinning machine. In conclusion, ANN and statistical model both have given satisfactory predictions;
however, the predictions of ANN gave relatively more reliable results than those of statistical models. Since the prediction
capacity of statistical models is also obtained as satisfactory, it can also be used for breaking elongation (%) prediction
of yarns because of its simplicity and non-complex structure. In addition, it is also found in this study that yarn count,
rotor speed and breaking elongation of polyester-viscose fibers and the blend ratios of these fibers in the yarn have major
effects on yarn breaking elongation. 相似文献
9.
Berrin Yilmaz 《Fibers and Polymers》2011,12(8):1091-1098
A tire is a composite of rubber and reinforcing materials. Polymeric materials used as reinforcing components are usually
synthetic yarns. These synthetic yarns have high tenacity, they are made of continuous multifilaments. The yarns are converted
in the cord form to provide desired mechanical, thermal and adhesion properties by a series of conversion processes. Besides
of multifilament synthetic cords, there are some specific areas in which single ply monofilament cords have been utilized
as a reinforcing element. In this study, new cord structures have been developed by using monofilament yarns and by imitating
multifilament cords. New cord structures exhibited some very interesting cord properties compared to both single ply monofilament
cord and multifilament cords. Monofilament yarns having diameter between 0.23 and 0.50 mm have been twisted together from
3 to 6 plies based on mixed Taguchi model to form cords. Nylon 6.6 and Polyester monofilament yarns have been selected because
of common application of their multifilament counterpart yarns in tire carcass and capply. The twisted monofilament cords
have been adhesive treated to produce cords ready to adhere rubber. The mechanical properties, thermal stability, adhesion
with rubber, fatigue properties under dynamic conditions, retention of properties after curing and microscopic analysis of
the cords have been analyzed. The cords have been found to possess some benefits for tire carcass, breaker, belt and belt
protective layer applications with their superior fatigue performance, cut resistance, stiffness, ligth weigth etc. 相似文献
10.
In present work, PET FDY has been used to blend with diacetate filaments by air texturing process and core-and-effect air-textured
yarns have been produced. The influences of both over-feeds of core and effect components on properties of textured yarns
were mainly examined. It was observed that a spun-like effect of diacetate filaments occurred during air texturing and there
were a little amount of free fiber ends besides loops on blended air textured yarns, while the number of free fiber ends changed
little with variation in over-feeds. The tenacity of textured yarns decreased with increase in over-feeds of effect or core
component. The breaking elongation increased with increase in over-feed of effect component, but decreased with increase in
over-feed of core component. The yarn stability improves when both over-feeds are increased. The effect of over-feeds on boiling
water shrinkage shows no clear trend. The core and average diameters are higher at high over-feed of effect component, but
the over-feed of core component exhibits little effect on yarn diameters. The number and size of loops are increase with increased
over-feed of effect component. 相似文献
11.
In this work, the effect of optimum drafting condition on the drafting behavior and yarn quality of the bamboo charcoal-modified
fiber blended spun yarns were studied. We measured the drafting force and drafting force variance, CV% of the bamboo charcoal-modified
Polyester/Cotton (BCP/C) blended roving and bamboo charcoal-modified Rayon/Cotton (BCR/C) blended roving to examine the influence
of the roller gauge and drafting ratio on drafting behavior and yarn quality. We understand that the drafting force of the
bamboo charcoal-modified fiber blended roving follow the same trend as that for the regular P/C and R/C blend roving. However,
the drafting force presents some difference in characteristics between these bamboo charcoal-modified fiber blended rovings.
To correlate the drafting force variation, CV% and the bamboo charcoal-modified fiber blended spun yarn properties, we evaluated
the yarn quality and investigate the yarn quality index in conjunction with the break drafting ratio. Therefore, in this work,
we can obtain the best optimum drafting conditions for bamboo charcoal-modified fiber blended spun yarns; for the 19.7 tex
of BCP70/C30 blend spun yarn was under the roller gauge of 54 mm at the draft ratio of 1.3, whereas, for the 19.7 tex of BCR40/C60
blend spun yarn was under the roller gauge of 54 mm at the draft ratio of 1.2. 相似文献
12.
The tensile properties of spun yarns decisively influence its performance in various mechanical processing stages. This study
is primarily aimed at simultaneous analysis of two tensile properties of spun yarns namely tenacity and breaking strain, which
play crucial role in determining the frequency of warping breaks. The threshold values of yarn tenacity and breaking strain
required for 20’s Ne carded cotton yarn to sustain the imposed stresses and strains during warping process have been determined
using a bivariate normal distribution model. This study opens up the possibility of minimizing end breakage rate in various
manufacturing processes of textile industry by engineering of spun yarns devoid of potential weak spots which are responsible
for breaks. 相似文献
13.
对苎麻长麻纺（复精梳）工艺中的苎麻预并条和头道精梳条进行牵切,然后分别将其在棉纺设备上进行并条、粗纱和细纱加工。探讨牵切纱断裂强度与捻系数的相互关系,并对比分析牵切纱与常规纱的质量。结果表明,牵切纱临界捻系数αt 在405左右,苎麻牵切精梳纱的条干、粗细节、棉结及3 mm以上的毛羽与苎麻常规精梳纱的接近,且断裂强度优于苎麻常规精梳纱的。 相似文献
14.
Wet electrospinning is a simple and efficient method to manufacture continuous nanofiber filaments. However, polyacrylonitrile nanofiber filaments collected using a static water bath are limited for application in certain areas due to their low degree of alignment and breaking stress values. To improve these properties, a novel countercurrent flowing liquid bath collector was combined with a multi-needle electrospinning device. The morphologies, crystalline structures, thermal behaviors and mechanical properties of filaments fabricated under different countercurrent bath liquid motion conditions were investigated. In addition, the forces acting on the nanofibers in the bundling triangular zone under countercurrent liquid bath motion were analyzed. The results showed that the average nanofiber diameter of the filaments decreased with an increase in bath solution motion forces. The maximum alignment degree and breaking stress of the nanofibers were 85 % and 0.63 cN/dtex, respectively, achieved using a liquid flow rate of 80 ml/min and water inlet diameter of 6 mm. The alignment degree of the assembled nanofibers in the bundling triangular zone could be increased by 57 % when using a countercurrent flowing liquid compared with a static liquid bath. 相似文献
15.
Mei-Chen Lin Ching-Wen Lou Ting An Lin Yueh-Sheng Chen Jia-Horng Lin 《Fibers and Polymers》2018,19(8):1596-1604
This study aims to develop biodegradable vascular stents that prevent permanent damage caused by rejection of the immune system of the human body. Polyvinyl alcohol (PVA) yarns are twisted to enhance their strength. The twisted yarns are braided and then coated with chitosan (CS). The CS-coated PVA vascular stents are chemically crosslinked with genipin (GP) to improve their flexibility and biodegradability. Their morphological characteristics are also observed using a stereoscopic microscope, and their properties are evaluated through scanning electron microscopy, Fourier transform infrared, bending test, biodegradability test, drug release measurement, and MTT assay. Results reveal that wet PVA-CS-GP vascular stents coated with multiple CS layers can maintain a tubular structure when they are bent. After crosslinking is performed, the compressive strength of the PVA-CS-GP stents is 17.04 times higher than that of pure PVA. The weight loss rate of the PVA-CS-GP vascular stents as <3 % after 30 days. The PVA-CS-GP vascular stents composed of 0.10 % heparin sodium show a good drug release effect. Biological activity test indicates that these stents exhibit good proliferation, and our structural model verifies that they are good vascular stents. 相似文献
16.
In this study artificial neural network (ANN) models have been designed to predict the ring cotton yarn properties from the
fiber properties measured on HVI (high volume instrument) system and the performance of ANN models have been compared with
our previous statistical models based on regression analysis. Yarn count, twist and roving properties were selected as input
variables as they give significant influence on yarn properties. In experimental part, a total of 180 cotton ring spun yarns
were produced using 15 different blends. The four yarn counts and three twist multipliers were chosen within the range of
Ne 20–35 and α
e 3.8–4.6 respectively. After measuring yarn tenacity and breaking elongation, evaluations of data were performed by using
ANN. Afterwards, sensitivity analysis results and coefficient of multiple determination (R2) values of ANN and regression models were compared. Our results show that ANN is more powerful tool than the regression models. 相似文献
17.
Lei Zhang Leng Han Yujun Wang Tianfu Zhao Xianxun Bao Masao Nakagaki 《Fibers and Polymers》2013,14(7):1190-1195
Spider dragline fiber is a high-performance biomaterial that has received much attention. To screen the outstanding spider dragline fibers, the mechanical properties and microstructures of dragline fibers collected from Nephia clavata, Nephia pilipes, Argiope bruennichi and Argiope amoena were investigated. It was found that the mechanical properties of spider dragline fiber were variable. Among the four different species, the larger spiders did not always extrude thicker dragline fibers and produce fibers with the maximum breaking force. The dragline fibers could sustain one to three times the body weight of the spider at a reeling speed of 20 mm/s. N. clavata dragline fiber showed a stronger breaking stress and initial modulus than that of N. pilipes, A. bruennichi and A. amoena. With an increasing reeling speed, the breaking strain decreased; the initial modulus increased in N. clavata, N. pilipes and A. bruennichi, but the breaking stress exhibited a different tendency. The results also revealed that dragline fiber of N. clavata contained the most β-sheet polypeptides and an excellent orientation of β-sheet molecular chains. 相似文献
18.
The mechanical and physical properties of spun yarns and fabrics depend not only on properties of constituent fibers, but also the yarn structure characterized by geometrical arrangement of fibers in the yarn body. Although there are many studies related to analyzing the migratory properties of spun yarns, there are no studies available about predicting yarn migration parameters. Therefore, the main aim of this research is to introduce a new approach to predict migratory properties of different kinds of spun yarns, namely siro, solo, compact and conventional ring-spun yarns. To achieve the objectives of the research, general physical and mechanical properties of spun yarns together with existing standards were thoroughly studied. Spun yarn migratory properties were predicted using intelligent technique of artificial neural network (ANN). Results signified that the ANN models can predict precisely the yarn migratory properties on the basis of a series of yarn physical and mechanical properties. 相似文献
19.
Khiari Ramzi Meksi Nizar Mhenni Farouk Belgacem Mohamed Naceur Mauret Evelyne 《Fibers and Polymers》2011,12(5):587-593
The chemical composition of date palm rachis wastes, which are widely available cellulosic biomass-based agricultural crops
in Tunisia, were characterized to determine if they had the potential for use as a starting raw material to prepare cellulose
derivatives. To accomplish this, several sodium cellulose carboxylmethylates (NaCMCs) were prepared and tested as sizing agents
for coating yarn. The synthesis of NaCMC was conducted in n-butanol containing NaOH (40 %) as a solvent mixture and monochloroacetic
acid (MAC) as the etherifying reagent. The NaCMC samples were characterized based on their degrees of substitution (DS) and
polymerization (DP). The prepared NaCMC samples were then tested as sizing agents for cotton yarn in textile applications.
Specifically, different NaCMC samples were used to prepare a coating bath, which was then applied to size a cotton yarn textile.
The quality of the coated yarns was subsequently evaluated by determining three parameters, yarn hairiness, the load at break,
and the elongation at break. The sizing performances of the NaCMCs prepared from date palm rachis wastes were then compared
with those of commercial NaCMC. The values of hairiness, breaking load, and breaking elongation of some of the NaCMC-treated
yarns were as high as those prepared using commercial additives as sizing agents. These findings indicate that the cellulose
derivatives prepared in this study are good candidates for alternatives to currently available additives. 相似文献
20.
The effect of spinning parameters on core-spun yarns properties manufactured using three-strand modified method (TSMM) was analyzed. Of the various spinning parameters, strand spacing, yarn linear density and yarn twist have a crucial effect on core-spun yarn properties. To achieve the objectives of this research, general physical properties of core-spun yarns together with existing standards were thoroughly studied. First of all, the strand spacing and yarn linear density were optimized. Afterwards, the effects of variation of yarn twist and sheath roving linear density on core-spun yarns properties were investigated. Finally, the physical and mechanical properties of TSMM yarns were compared with those of siro and conventional ring core-spun yarns counterparts. It was found that, the best strand spacing and yarn linear density to produce core-spun yarns are 8 mm and 45 tex, respectively. Results showed that, tenacity of TSMM yarns increases up to a certain twist level beyond which it reduces. The result confirmed that 45 tex yarns produced by three rovings of the same count are superior with regards to tenacity and hairiness. The optimized yarns produced by three-strand modified method enjoy superior physical and mechanical properties in comparison to the ring and siro core-spun yarns. 相似文献